高效液相色谱法测定饲料中喹乙醇的含量

实验建立了饲料中喹乙醇经过固相萃取净化后用高效液相色谱仪定量检测的方法。饲料经70%甲醇溶液提取、离心后,经中性氧化铝小柱净化后,过0.45μm滤膜上机定量测定。实验结果表明,喹乙醇浓度为0.1～100.0μg/ml时具有良好的线性关系,饲料中喹乙醇回收率范围均在80%～110%。与国家标准GB/T8381.7—2005《饲料中喹乙醇的测定:高效液相色谱法》相比,本方法的实验结果不仅完全符合国家标准的要求,增加的净化过程更能有效地保护高效液相色谱系统。     

猪饲料中莱克多巴胺的GC/MS快速测定

本实验对猪饲料中莱克多巴胺的气相色谱-质谱快速检测方法进行了研究.采用酸性甲醇-水提取饲料中的莱克多巴胺,经乙酸乙酯萃取和酸性氧化铝固相萃取柱净化,衍生化后用气相色谱-质谱法检测和确证.结果表明,方法平均回收率为70.8%～83.8%,日间变异系数为4.5%～11.1%(n=3),配合饲料检测限和定量限分别为0.5μg/g和1.0 μg/g,预混合饲料检测限和定量限分别为0.3 μg/g和0.7 μg/g.该方法适合饲料中莱克多巴胺的确证和定量分析.     

超高效液相色谱-串联质谱法检测饲料中喹烯酮和喹乙醇

本文应用超高效液相色谱-串联质谱技术,建立了饲料中喹烯酮和喹乙醇的检测方法。样品经0.1%甲酸乙腈溶液提取后,通过PRiME HLB固相萃取柱净化;采用0.1%甲酸乙腈溶液作为流动相进行梯度洗脱,经AtlantisT3色谱柱分离,通过多反应监测模式进行测定。在5～500 ng/mL时线性关系良好,相关系数均大于0.996。在0.2、0.4、2 mg/kg添加水平下,平均回收率为80%～95.5%,相对标准偏差均小于10%。检测限为0.06 mg/kg,定量限为0.2 mg/kg,该法准确、简单、快速。     

超高效液相色谱法测定饲料中地昔尼尔

本研究建立了超高效液相色谱测定饲料中地昔尼尔的方法。饲料样品经过乙腈提取,取5mL上清液氮气吹干,用20%甲醇溶液(含0.2%甲酸)溶解,经过Waters Oasis MCX固相萃取小柱净化,然后用Waters Acquity UPLC HSS T3色谱柱(2.1mm×100mmi.d.,1.8μm)分离,以甲醇和水为流动相进行洗脱,外标法定量。结果表明,地昔尼尔质量浓度在0.05～100μg/mL内线性良好,相关系数大于0.9999;在10～200mg/kg的添加水平,平均加标回收率为78.0%～86.3%;相对标准偏差为4.2%～6.1%;方法的检出限低至0.05mg/kg,定量下限低至0.1mg/kg。该方法简单、快速、灵敏,可满足饲料中地昔尼尔的快速筛选检测的要求。     

超高效液相色谱-电喷雾串联质谱法测定饲料中地昔尼尔

实验建立了超高效液相色谱-串联质谱测定饲料中地昔尼尔的方法。饲料样品经过乙腈提取,取部分上清液氮气吹干,用20%甲醇溶液(含0.2%甲酸)溶解,经过Waters Oasis MCX固相萃取小柱净化,然后用Waters Acquity UPLC HSS T3色谱柱(2.1mm×100mm i.d.,1.8μm)分离,以甲醇和水为流动相进行洗脱,外标法定量。对前处理及液相色谱和质谱条件进行优化。结果表明,地昔尼尔质量浓度在1～500μg/l范围内线性良好,相关系数大于0.998;在10～200μg/kg的添加水平,平均加标回收率为74.2%～83.8%;相对标准偏差为5.5%～7.5%;方法的检出限低至1.0μg/kg,定量下限低至2.0μg/kg。该方法灵敏、稳定性好,可满足饲料中地昔尼尔的检测与确证的要求。     

气相色谱/质谱法测定饲料中三唑仑的含量

本实验建立了检测饲料中三唑仑的气相色谱/质谱法。样品经有机溶剂提取,阳离子固相萃取小柱净化后注入气相色谱质谱仪进行测定,并且经质谱确证。结果表明,三唑仑在0.1～5.0μg/mL范围内具有良好的线性关系,方法的回收率、精密度较高。     

LC-MS/MS结合定量触发相关MS/MS扫描功能同时定性确证和定量测定饲料中的违禁药物喹乙醇

本实验利用定量触发相关MS/MS扫描(QED-MS/MS)功能,建立饲料中喹乙醇的同时定性确证和定量测定LC-MS/MS方法。饲料中喹乙醇经5%甲醇-水溶液提取,Oasis HLB固相萃取柱净化后,通过LC-MS/MS分析。LC-MS/MS采用Zorbax SB C18柱(3.5μm,2.1×150 mm),0.2%乙酸-甲醇梯度洗脱,加热电喷雾离子化,选择性反应监测m/z 264>212作为定量测定,同时以数据依赖扫描模式对m/z 150～265扫描,作为定性确证结果。结果表明:本方法在0.2～10 mg/kg范围内线性关系良好,最低同时定性定量限为0.2 mg/kg。因此基于QED-MS/MS的LC-MS/MS方法可用于饲料中喹乙醇的检测。     

高效液相色谱串联质谱法测定渔业水体及渔业饲料中的五氯苯酚

本文建立了一种简单、快速测定渔业水体和渔业饲料中五氯苯酚的液相色谱串联质谱分析方法。渔业水体采取固相萃取进行富集净化,渔业饲料样品经氨化乙腈提取,MAX固相萃取小柱净化,质谱采用选择反应监测负离子模式测定进行分析。结果表明:方法线性为0.5～50 ng/mL,相关系数大于0.9999;渔业水体的检出限(LOD)和定量限(LOQ)为0.05μg/L和0.1μg/L,渔业饲料的LOD和LOQ为0.8μg/kg和1.6μg/kg,该方法在水样和渔业饲料样品中的平均加标回收率为78.6%～92.1%。采用该方法对长沙市周边的湖泊和池塘地表水和渔业饲料样品进行检测,在水样中测得五氯苯酚浓度为0.64～1.22μg/L。     

超高效液相色谱-串联质谱法测定饲料中的恩诺沙星和喹乙醇药物的含量

试验建立了同时测定饲料中恩诺沙星和喹乙醇药物含量的超高效液相色谱-串联质谱(UPLC/MS/MS)分析方法。采用80%乙腈(含1%甲酸)作为样品的提取溶液,经HLB固相萃取柱净化后上机测定。在正离子模式下通过两对离子对进行定性和定量分析。结果显示,恩诺沙星和喹乙醇在5~100μg/l范围内线性关系良好,相关系数r均大于0.998;空白饲料在0.1、0.2、0.5 mg/kg的添加浓度上的回收率均在70%~90%之间;批内、批间相对偏差(RSD)均小于20%;本方法对饲料中恩诺沙星和喹乙醇的定量限为0.1 mg/kg(S/N10),检测限为0.05 mg/kg(S/N3)。     

牛肝中氯舒隆残留检测高效液相色谱-串联质谱法研究

研究了采用固相萃取净化,高效液相色谱-串联质谱(HPLC-MS/MS)法测定牛肝中氯舒隆残留量的方法.样品用乙腈提取,HLB固相萃取小柱净化后,HPLC-MS/MS方法检测.离子源采用电喷雾负离子方式(ESI-),多反应监测(MRM)模式进行采集,外标法定量.结果表明:方法检测限为2 μg/kg,定量限为5 μg/kg.在5、20、100 μg/kg三个添加浓度范围内,方法的平均回收率为86.6%～93.5%;方法RSD≤6.8%.     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein     

Avian brood parasitism — a growing research area in behavioral ecology (part Ⅱ)

正We are pleased to publish the second special issue on avian brood parasitism and to be responsible guest editors for the two special issues of Chinese Birds (Vol. 3, No. 4, 2012 and Vol. 4, No. 1, 2013), entitled "Avian Brood Parasitism - A Growing Research Area in Behavioral Ecology". The first issue was published in December 2012. The goal of the two special issues is to publish accumulated knowledge and some of the recent developments in     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -